The lights dimmed at the May Day stadium and a rapt crowd of 150,000 fell silent at the start of a spectacle considered so important to North Korean leader Kim Jong Il that it has merited a rare, if limited, opening to the outside world.

North Korea has creaked open its doors for Arirang, a festival that celebrates national pride and, this year, commemorates the 60th anniversary of the Stalinist state's ruling Workers' Party. Performers, who numbered almost as many as the spectators, won furious applause for their coordinated displays of rhythmic gymnastics, flying acrobatics, traditional dancing and military taekwondo routines -- all synchronized to a massive video and laser light show.

"You are about to see the true identity of our great nation," a North Korean guide proudly told a cluster of South Korean tourists as one evening session opened last week. "Please pay attention. This is our message to the world."

North Korea has rolled out the red carpet this month in exceptional style. Tour operators, diplomats and analysts describe the gathering of foreigners as the largest since Kim inherited the leadership on the death of his father and North Korea's founder, Kim Il Sung, in 1994.

The guests have included hundreds of Americans, typically barred by the North Koreans. Among them have been New Mexico Gov. Bill Richardson and former CBS News anchorman Dan Rather. The festival has brought official delegations from China, Russia and Cuba as well as ranking visitors from Mexico and a host of other nations. Thousands of South Korean tourists, usually forbidden to travel into the North Korean capital of Pyongyang, are also being embraced during October in this spruced-up city.

The North Koreans have not offered an explanation for the strictly controlled and likely temporary opening. But analysts have said it amounts to a demonstration of public support for Kim, 63, in which hundreds of thousands of North Koreans are attending the festival -- many walking for days to reach the stadium. The festival is being so well attended, North Korean officials said, that its original run of two weeks was extended to the entire month of October.

Meanwhile, modest economic reforms made in North Korea since 2002 appear to have somewhat eased the country's bitter poverty and once-rampant starvation. That at least seemed true within the relatively affluent capital of Pyongyang, where people look to be well fed, many buildings have been newly refurbished and street vendors are surprisingly outgoing and eager to make sales to foreign visitors.

Analysts said the scenes are the picture-perfect snapshots Kim is eager to project. He largely shut foreigners out of the last Arirang festival, in 2002, but he has far different considerations this time. First and foremost is the need to reflect his government's solidity and strength during protracted negotiations to dismantle its nuclear weapons programs. The talks are expected to resume in Beijing within two weeks.

"This is 'invitation diplomacy' -- a tool Kim's father used to use to great effect," said Noriyuki Suzuki, director of Tokyo-based Radiopress, which monitors television and radio broadcasts in North Korea. "Kim is trying to show how strong and stable North Korea is -- how firmly he is in control and how popular he remains with the people. Unless there are select groups of foreigners there to see this, his message will not get out loud and clear."

The North Koreans also appear eager to portray themselves as flexible. Richardson, for example, said high-ranking North Koreans appeared to backtrack on a threat they made in September to expel foreign food-aid workers on grounds they were no longer needed. Richardson, who was in Pyongyang for four days last week, served as U.S. ambassador to the United Nations during the Clinton administration and has been long considered by the North Koreans as a trusted intermediary.

"The atmosphere there is the best I've seen in 15 years," Richardson said during a stop in Tokyo after his visit. He said he went to Pyongyang by personal invitation from the government, and not as an official U.S. envoy. "Of course, there are still problems," he added, "but the atmosphere is much improved."

He said the North Koreans, who contend that they had a bumper farm crop this year, would allow as many as 60 of the roughly 100 foreign aid workers in North Korea to stay.

Abraham DeKock, deputy country director for the U.N. World Food Program in Pyongyang, said in a telephone interview that the North Koreans had yet to confirm that offer. But he added that a North Korean delegation is scheduled later this week to visit the program's Rome headquarters, where officials hope to hash out an agreement.

Return visitors to North Korea, meanwhile, have noted that anti-American propaganda and slogans have been taken down in the capital.

Regardless of motives, the window of opportunity is providing thousands of outsiders with a rare glimpse inside the heart of one of the world's least penetrated societies.

During a 40-hour, strictly monitored visit by a reporter accompanying a South Korean tour group, there were odd scenes mixed with a feeling of real change.

At the run-down and mostly empty airport, a dozen young North Korean women stood in front of outdoor stalls, calling to tourists with a capitalist verve not unlike that of street vendors in other Asian cities. "Come and see our snake whiskey!" they beckoned. "It's all natural! We take euros -- and dollars."

Visitors were not permitted to speak with anyone other than designated North Korean shop clerks and guides. The South Koreans, who had paid $1,000 each for the trip, included members of citizen groups that support contacts with the North, along with curiosity-seekers and older South Koreans born in the North before the Korean War divided the peninsula.

Among them was Yoon Seung Bin, 78, a retired businessman who said he last saw Pyongyang 60 years ago when his father was executed by the communists.

"I thought I was going to die without visiting my home again," he said with tears in his eyes as he watched Pyongyang residents wave passionately to the tour group as it passed by in a bus.

The performance at the May Day stadium dazzled the visitors with its flawless choreography and dogged loyalty to Kim and his father. The crowd roared as massive images of the elder Kim, known as the Great Leader, and the younger Kim, known as the Dear Leader, were unfurled. "No one can defeat us!" sang a battalion of marching soldiers. At the same time, people dressed as flying angels soared from tethers above the stadium, singing, "Oh, we are so happy!"

The crowd joined in the patriotic songs and slogans, which rapidly changed tempo and theme. One minute, performers belted out a chorus of "Let the Moon Shine on the Path of Our Great Leader's Struggle Against the Japanese Colonizers," referring to Japan's long and still freshly remembered occupation of the Korean Peninsula in the first half of 20th century. Next, they crooned "Science and Technology to the Most Advanced Level," sung to a melody reminiscent of the theme from "Star Wars."

The spectacle often seemed particularly aimed at the South Korean visitors. At one point, participants held up flashcards creating a montage of South and North Korean children, while uttering the chant: "How much longer do we have to be split due to foreign forces?" Soon, most of the visiting South Koreans were chiming in for the chorus: "We are one."

Faiola reported from Tokyo.

North Koreans perform during the Arirang festival, which this year is marking the 60th anniversary of the founding of the ruling Workers' Party. The festival performances are highly choreographed and include rhythmic gymnastics, flying acrobatics and dancing.